What is the recommended dose of ertapenem (IM) for a patient with impaired renal function?

Ertapenem IM Dosing for Patient with Renal Impairment

For a patient with BUN 31 and creatinine 1.8, the appropriate ertapenem IM dose is 500 mg once daily. 1

Assessment of Renal Function

• BUN 31 and creatinine 1.8 indicate renal impairment that requires dosage adjustment 1
• When only serum creatinine is available, creatinine clearance can be estimated using the Cockcroft-Gault equation 1:
  • For males: (weight in kg) × (140-age in years) ÷ (72 × serum creatinine in mg/dL)
  • For females: 0.85 × value calculated for males

Dosing Recommendations

• For patients with severe renal impairment (creatinine clearance ≤30 mL/min/1.73 m²), ertapenem dose should be reduced to 500 mg daily 1
• The standard 1 gram dose is only appropriate for patients with creatinine clearance >30 mL/min/1.73 m² 1
• Intramuscular administration is appropriate for up to 7 days of treatment 1

Administration Guidelines for IM Ertapenem

• Reconstitute 1 g vial with 3.2 mL of 1% lidocaine HCl injection (without epinephrine) 1, 2
• Shake vial thoroughly to form solution (concentration approximately 280 mg/mL) 1
• Administer by deep intramuscular injection into a large muscle mass (gluteal muscles or lateral part of thigh) 1, 2
• Use reconstituted IM solution within 1 hour after preparation 1
• For the 500 mg dose, use half of the reconstituted solution and discard the remainder 1

Special Considerations for Hemodialysis

• If the patient is on hemodialysis, a supplementary dose of 150 mg is recommended following hemodialysis session when ertapenem is given within 6 hours prior to hemodialysis 1
• If ertapenem is given at least 6 hours prior to hemodialysis, no supplementary dose is needed 1

Efficacy and Safety

• Despite dose reduction, ertapenem maintains efficacy in patients with renal impairment when dosed appropriately 3
• IM ertapenem (reconstituted in lidocaine) is generally well tolerated with a safety profile comparable to IM ceftriaxone 2
• Common local injection site reactions include tenderness and pain, which are typically mild to moderate in severity 2
• The relative bioavailability of the IM formulation is 92% compared to IV administration 4

Monitoring

• Monitor for clinical response and potential adverse effects 1, 2
• No specific laboratory monitoring is required for ertapenem administration, but continued assessment of renal function is prudent in patients with impaired renal function 1
• Consider obtaining a 24-hour urine collection for more accurate assessment of renal function in patients with borderline renal impairment 5